DESCRIPTION (Verbatim from the application): The objective of this application is to understand the role of a CHD protein in determination of developmental identity in Arabidopsis thaliana. CHD proteins have been implicated as chromatin remodeling factors are found in many diverse organisms ranging from yeast to man. In Arabidopsis thaliana, the pkl mutation is defective in the gibberellin signal transduction pathway and in the developmental transition form embryo to seedling. PKL has been cloned and codes for a CHD family member. We are interested in understanding the role of this CHD protein in regulation of developmental identity and GA signal transduction. To identify possible mechanisms by which PKL is regulated, expression of PKL transcript and protein will be characterized. Genes will be identified that are directly regulated by PKL and therefore potentially involved in regulation of developmental identity and GA signal transduction. Proteins that interact with PKL will be identified by two-hybrid analysis and affinity chromatography in an attempt to identify potential co-factors that may regulate PKL activity. Additional factors that are involved in regulation of developmental identity, gibberellin signal transduction, and/or chromatin remodeling may be identified based on a genetic screen. By carrying out these experimental aims, it is hoped that a greater understanding will be achieved of the role of CHD proteins in regulation of development in plants and perhaps all eukaryotes.